Process of separating acid from petroleum sludge.



J. L. GRAY.

PROCESS OF SEPARATING ACID FROM PETROLEUM SLUDGE.

APPLICATION FILED JUNE 24, 1905.

Patented June 1, 1909.

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JOHN LATHROP GRAY, OF ELIZABETH, NEW JERSEY.

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Specification of Letters Patent.

033 SEEARATING AGED FROM PETROLEWJE SLUDG-E.

Patented June 1, 1909.-

applicetlon filed June 2%, lfi fifi. Serial No. 266,765.

.lt is customary in the artto separate the acid from etroleum sludge by digesting the sludge wit water and steam or water and air, or Water, steam and air so that the separated and recovered acid is 4'0 degrees to 50 de recs gravity Baum.

' 'y additional digesting of the sludge, or by using more water and steam than is customary in the original treatment by washing the sludge with Water and simultaneously agitating it by steam or air, no doubt more acid might be secured but it would be at a gravity too low to pay for reconcentrating for use. i

My method consists essentially in digesting the petroleum sludge first with relatiwly weak acid, of approximately 1.5 degrees gravity, using sul'l'icient of the acid so that it will absorb sullioicnt of the stronger acid ol the sludge to raise the gravity and produce a body of separated acid which will show or degrees gravity Bennie, and even lower. I then digest a second time, using a relatively still weaker acid or water, until 1 have nocumulated by absorption nearly all the remaining acid in the sludge. rated by the iii-st treatment sulliciontly strong to be recovered with economy, butthe acid from the succeeding treatment is relatively too weak to be economically rocon-.

con-crates. lhavo discovered, however, that the acid from the second treatment serves as an cll'cctivc first wash for the reason that a great deal of acid is destroyed by the chemical heat generated by using water for tho first Wash, this loss in acid being due to the combination of some of the hydro-carbons ol' the sludge withsulfur from the acid allowing the SO: radical from the acid to escape as worthless gas, and by using the weaker acid a relatively lower t8II1)61tLtU1e is secured and less acid is destroys and the hydro-carbons T he acid sopa oil, the resulting syrup.

resent are less injured for the further manu- Iacture into asphalt Petroleum is composed of many and various hydro-carbons, some of which are unsaturated. In the treatment of petroleum when sulfuric acid is introduced it combines with these unsaturated hydro carbons and separates them from the main body of the combination of the unsaturated hydrocarbons, the sulfuric acid and a percentage of mechanically entrained oil. On settling, with or without heating, the mechanically entrained oil rises to the top, and 1 pump it o'll', leaving what may be termed a pure sludge.

\ 1 In the accompanying drawing, illustrating a form of apparatus which may be used in carrying out this process 1 represents a separator tank. 2 represents a pipe through which the digesting medium, Water or Weak acid, may enter. 3 represents a steam line and 4 an air line, both ofwhich lead into the separator tank and discharge at the bottom. An outlet pipe 5, valved at 6, leads from the bottom of the separator tank. Such an apparatus will constitute a separator for a single treatment. For the additional treatments to provide for removing another layer or grade from the top as well as from the bottom, I employ an adjunctive pipe device comprising a branch pipe 18 leading into a main pipe The pipe 18is valved at 19, and passes through, in the form illustrated, the side of the separator tank 1. Connecting with the pipe 18 is a swing section 20,. having a joint at 21 and adapted to be onerated either by hand. or )OWQI through tie medium o'r a chain 22. This swing joint sec tion may be lifted in and down according to the height of the light rade or the top layer the tank so that tlie top layer may be {awn oil through its separator connection. As an example of the mode of carrying out my process .l. may .ake IOU lbs. of an. average sludge. To this inlay add, through the iipe 2,100 lbs. ol 15 Baum gravity .sulturic acid. I. then. agitate for about one hour with steam or air, or both steam and air. I use the steam on heavy sludge and on the lighter grades I use either air or steam, or both.- I then draw oil 78 lbs.of 37; Baum acid'a'nd 201; lbs. of a light grade of unsaturated hydro-carbons about the consistency of 1 then add 40 lbs. of Water to the remaining sludgeand agitate one hour with sludge being really at air or steam, or both. 1 then draw oil 64 lbs. of about 17 1- Baum gravity acid, 2 lbs.

of an intermediate grade of about the consistency ol' molasses, leaving 36 lbs. of a re-' maining heavy sludge. In ordinary practice in each case the mass will separate into layers, the relatively light grade of separated unsaturated hydro-carbons on top, the relatively heavy remaining sludge next and the acid at the bottom. I. employ the Weak acid resulting from this second digesting in the first digesting of succeeding operations.

In a companion application Serial No. 266,763, I have described and claimed a process of producing pitch or asphaltum either from the original body of sludge or from any of the rades into which, by a process described in another companion application, (Serial No. 266,764, I may separate it. In carrying out the process of No. 266,763 I digest the acid sludge until the maj or part of the acid has been removed, then heat the mass beyond the condensing point of steam, and, finally digest the mass by a steam spray until it is converted into pitch.

In carrying out the process of No. 266,764, I digest the acid sludge until the mass separates into divisions of separated unsaturated hydrocarbons, weak acid, and a heavy residuum, the remaining unseparated sludge.

It will be apparent that I may employ effectively the process of this application No.

' 266,765, in carrying out the process of appli--' cation No. 266,764 and as a .neliminary step in carrying out the process ol my application No. 266,763. In carrying out these processes the preceding pumping oil of the mechanically entrained oil leaves only the sludge to be treated by the process of this application, a d in the subsequent process of producing pitch. or asphaltuin, described and claimed 1.: the aforesaid. companion applications, prevents the presence of a combination of the entrained oil with any of the acid which might be formed under the high temperatures employed in carrying out the separatnig process or the pitch and asphaltum" process.

My process of removing the acid from the sludge, therefore, results in securing a larger amount of acid than has hitherto been derived, and at the same time forms a valuable preliminary process to my above described invention for treating the petroleum sludge to secure pitch orasphaltum. 'For by my treatment in accordance with the recess of this application I not only save a arge part of the acid from the sludge, but by removing the acid I leave the sludge in a favorable condition for being treated by my process of securing pitch.

Having fully described my invention, What I claim is 1. The process of separating acid from sludge which consists in Washing or digesting a sludge from which the major port-ion of the acid has been separated, and employing the accumulated acid of a succeeding Washing or digesting to separate the acid from another body of sludge. I

2. The process of separating acid from sludge in. two washings or digestings in which the second week acid separation is employed in the first Washing or digesting of a succeeding body of sludge.

. 3. The process of se arating acid from sludge which consists in washing or digesting the sludge With a Weak acid solution,

In testimony whereof I aflix my signature, in presence of two witnesses.

' JOHN LATER-OP GRAY. \Vitnesses FRANK B. Mason, THOMAS Taavm GRAY. 

